A plan by Dallas-based electricity distributor Oncor to expand its Texas transmission network gained approval Thursday from the Public Utility Commission of Texas.

Oncor and its majority owner, San Diego-based Sempra Energy, reached a deal in October to buy the Hunt family-owned InfraREIT. Texas regulators' approval was the final signoff needed to complete the $1.275 billion deal.

"We look forward to continuing to advance our growth strategy in Texas and the U.S. Gulf Coast region," Sempra CEO Jeffrey W. Martin said in a statement. Sempra bought Oncor in March 2018 in a deal valued at $9.45 billion.

The InfraREIT deal gives Oncor and Sempra control of Hunt-owned infrastructure, including power lines in the Panhandle and West Texas. InfraREIT shareholders approved it in February.

Sempra also acquired a 50 percent stake valued at $98 million in Sharyland Utilities, another Hunt-owned company serving South Texas. The remainder of Sharyland would still be controlled by Hunter L. Hunt and other family members.

The transactions are expected to close by the end of this month, the companies said.

"When our acquisition of InfraREIT is complete, we will expand our transmission footprint and be better positioned to support the long-term needs of the ERCOT market," Oncor CEO Allen Nye said in a statement.

Oncor operates Texas' largest distribution and transmission system, delivering power to more than 3.6 million homes and businesses. Its service area stretches from the Oklahoma border down through Dallas-Fort Worth to Round Rock and includes a separate swath of land in West Texas covering Odessa, Midland and the surrounding area.